The present invention relates generally to brushes and the art of brush making, and more particularly, to brushes having monofilament bristles and methods of assembling monofilament bristle sub-assemblies to brush bodies.
Brush making involves the attachment of bristles to a brush body. In one type of brush, known as the xe2x80x9csolid block/staple set,xe2x80x9d a solid block acting as the brush body is drilled, molded, or otherwise worked to form an array of holes. Individual tufts are placed in individual holes and secured to the block by wire staples, plugs or other anchoring means. Hand drawn brushes are similar except that the tufts are secured by drawing them through the holes with an elongated strand.
Another type of brush employs a xe2x80x9cferrule and monofilamentsxe2x80x9d technique for attaching the bristles to the brush body. A cluster of monofilaments and cavity creating spacers are inserted into a ferrule and set with a binding resin. Ferrule brushes, such as the paint brush, are used to primarily apply liquid or viscous solutions.
In metal strip brushes, fibers are held in a xe2x80x9cUxe2x80x9d shaped channel of a metal strip by an anchoring wire, string, or monofilament. The channel is then crimped closed to mechanically clamp the proximal end portions of the monofilaments and anchor wire within the strip. Once formed, the brush-strips can be attached to brush bodies or otherwise shaped for specific applications. Fused brushes are those in which polymeric tufts are fused directly to a brush body that is preferably made of the same material. One variation of fused brushes employs ultrasonic welding to secure polymeric fibers directly to a base.
With respect to the toothbrush, it is now commonplace to employ nylon monofilaments that are grouped together to form xe2x80x9cbristle tufts.xe2x80x9d Each bristle tuft is typically arranged in a circular cluster, and a complete bristle head includes a matrix of bristle tufts arranged in rows or other patterns. The folded proximal bases of the bristle tufts are typically embedded and held in place by an anchor wire that extends across the field of the tufts and into the polymeric material that forms the head portion of the toothbrush body, while the distal ends extend upwardly therefrom, often terminating in a common plane. A more recent tufting method employs the process of cutting the tuft of monofilaments to the desired length, heat fusing the proximal ends and embedding the fused proximal ends into the polymeric material of the toothbrush head.
More recent innovations in the toothbrush art have included bristle tufts cut to provide differing lengths to provide an array of shorter and longer tufts to achieve a desired action on the user""s teeth. In some tufts the monofilaments are of differing length. While these improvements can result in better functional aspects of the toothbrush, few innovations have been made over the years in techniques for manufacturing the toothbrush head; this is particularly evident in the manner in which bristles are assembled with the brush body.
In all types of known brushes, the assembly process can represent a substantial portion of the cost of manufacture since individual bristle filaments have to be held in a desired grouping and then bound to the brush body in a manner that ensures that the bristle filaments do not become detached during use. Also, recycling becomes more problematic for brushes which employ metal staples or other combinations of different classes of materials (plastics and metals, for example) in one structure.
A continuing need exists for improved brush designs and methods of manufacturing brushes which are efficient and cost effective.
An object of the present invention is to provide means to expand brush design beyond the range possible with current tufting techniques.
An object of the present invention is to provide means to expand brush design beyond the range possible with current tufting techniques.
Another object of the present invention is to provide a bristle sub-assembly for a brush in which individual filaments are positionally fixed with respect to each other prior to connection to a brush body.
Still another object of the present invention is to provide a method of assembling brushes in which bristle sub-assemblies can be permanently connected to the brush body or, alternatively, detachably connected for subsequent replacement, thereby avoiding wastefully discarding otherwise functional brush bodies.
These and other objects are met by providing a bristle sub-assembly which includes a base string and a plurality of polymeric monofilaments connected transversely to the base string. Each monofilament, when connected to the base string. Each monofilament, when connected to the base string, forms a pair of monofilament segments, and the monofilament segments are disposed in two rows along the base string. The monofilament segments of the two rows extend outwardly from the base string to form a V-shaped bristle string which can be used in a variety of different brush applications.
In an alternative embodiment, the bristle sub-assembly includes a plurality of monofilament loops connected to a base string. Each loop is connected transversely to the base string to form a pair of loop segments extending outwardly from opposite sides of the base string to form two rows of loop segments.
Two or more looped or cut monofilament sub-assemblies can be twisted or braided together to form cylindrical structures having value in many applications, such as brushes.
The bristle sub-assemblies can be attached to brush bodies in a variety of ways to forth unique brush/bristle assemblies.
Other objects and features of the invention will become more apparent from the following detailed description when taken in conjunction with the illustrative embodiments in the accompanying drawings.